CA1212158A - Insulated conductor having adhesive overcoat - Google Patents
Insulated conductor having adhesive overcoatInfo
- Publication number
- CA1212158A CA1212158A CA000446630A CA446630A CA1212158A CA 1212158 A CA1212158 A CA 1212158A CA 000446630 A CA000446630 A CA 000446630A CA 446630 A CA446630 A CA 446630A CA 1212158 A CA1212158 A CA 1212158A
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- CA
- Canada
- Prior art keywords
- coating
- conductor
- cured
- stage
- liquid resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Adhesives Or Adhesive Processes (AREA)
- Organic Insulating Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed is a conductor coated with a fused and cured powder applied insulating coating over which is a coating of an ultraviolet B-stageable, thermally C-stageable liquid resin. The coating is cured to the B-stage and strands of the conductor are placed side-by-side. The coating is then cured to the C-stage which fuses the strands of the conductor into a solid mass. The adhesive coated conductors may be used to form transformer coils, transposed cables, or other articles.
Disclosed is a conductor coated with a fused and cured powder applied insulating coating over which is a coating of an ultraviolet B-stageable, thermally C-stageable liquid resin. The coating is cured to the B-stage and strands of the conductor are placed side-by-side. The coating is then cured to the C-stage which fuses the strands of the conductor into a solid mass. The adhesive coated conductors may be used to form transformer coils, transposed cables, or other articles.
Description
1~2~2`lls,~
1 50,541 INSULATED CONDUCTOR HAVING
ADHESIVE OVERCOAT
BACKGROUND OF THE INVENTION
Electrical failure of transformer coils, trays-posed cables, and other electrical equipment can occur when short circuit forces or mechanical abuse damage insulation. The mechanical strength of insulated coils and cables can be increased by bonding the individual insulated electrical conductor together into a single mass. This has been accomplished by placing adhesive coated paper in between the layers of conductors. How-ever, while this increases strength and reduces insulation damage, it also increases the cellulosic content of the electrical apparatus. Cellulose is undesirable if certain dielectric fluids are present because they react with cellulose to produce compounds which increase the conduct lo tivity of the fluid. Another technique for forming single mass out of multiple conductors is to cover the conductors with an adhesive either before or after the conductors have been juxtaposed. While this technique has also worked, it involves an additional step, and difficult ties may be encountered in obtaining good adhesion between the insulation and the adhesive.
SUMMARY OF THE INVENTION
We have discovered a method of preparing an adhesively coated insulated conductor which can be bonded I to itself to form a solid mass which is resistant to ~.~
Lo
1 50,541 INSULATED CONDUCTOR HAVING
ADHESIVE OVERCOAT
BACKGROUND OF THE INVENTION
Electrical failure of transformer coils, trays-posed cables, and other electrical equipment can occur when short circuit forces or mechanical abuse damage insulation. The mechanical strength of insulated coils and cables can be increased by bonding the individual insulated electrical conductor together into a single mass. This has been accomplished by placing adhesive coated paper in between the layers of conductors. How-ever, while this increases strength and reduces insulation damage, it also increases the cellulosic content of the electrical apparatus. Cellulose is undesirable if certain dielectric fluids are present because they react with cellulose to produce compounds which increase the conduct lo tivity of the fluid. Another technique for forming single mass out of multiple conductors is to cover the conductors with an adhesive either before or after the conductors have been juxtaposed. While this technique has also worked, it involves an additional step, and difficult ties may be encountered in obtaining good adhesion between the insulation and the adhesive.
SUMMARY OF THE INVENTION
We have discovered a method of preparing an adhesively coated insulated conductor which can be bonded I to itself to form a solid mass which is resistant to ~.~
Lo
2 50,541 electrical stress and mechanical abuse. The adhesively coated conductor according to this invention can be made in a single pass in a manufacturing process that requires very little space. The adhesive overcoat can be rapidly cured to the B-stage with ultraviolet light ( W ) which requires less energy than a thermal cure. It can then be easily thermally cured to C-stage (i.e., completely cured) once the conductors have been formed into a coil or cable.
Since the overcoat is 100% solids no solvent is evolved during curing and thus problems of air pollution and the collection and containment of vaporized solvent are avoided. The adhesive coated conductor has an excellent shelf life and can be stored for long periods of time prior to use. The overcoat does not flake and adds to the insulating qualities of the undercoat.
While ultraviolet curable compositions are not meant to be cured by heat, we have found that such combo-sessions can be very usefully adapted to producing adhesive coatings by only partially curing them with ultraviolet light and later completing the cure with heat. In spite of this unusual us ox W compositions, we have obtained excellent adherence between bonded conductors, and no adverse reactions have been observed that have lowered electrical or mechanical properties.
US Surprisingly, we have discovered that the over-coat has a synergistic interaction with a powder coated undercoat in that the dielectric strength of the overcoat on top of the undercoat is greater than the sum of the dielectric strengths of the two coatings by themselves.
RELEVANT ART
US. Patent 3,619,259 and 3,911,202 disclose W
polymerization of continuous films which may be used for the purpose of electrical insulation.
US. Patents 4,184,001 and 4,268,659 disclose US
curable compositions specifically for use as insulation of electric wires.
Since the overcoat is 100% solids no solvent is evolved during curing and thus problems of air pollution and the collection and containment of vaporized solvent are avoided. The adhesive coated conductor has an excellent shelf life and can be stored for long periods of time prior to use. The overcoat does not flake and adds to the insulating qualities of the undercoat.
While ultraviolet curable compositions are not meant to be cured by heat, we have found that such combo-sessions can be very usefully adapted to producing adhesive coatings by only partially curing them with ultraviolet light and later completing the cure with heat. In spite of this unusual us ox W compositions, we have obtained excellent adherence between bonded conductors, and no adverse reactions have been observed that have lowered electrical or mechanical properties.
US Surprisingly, we have discovered that the over-coat has a synergistic interaction with a powder coated undercoat in that the dielectric strength of the overcoat on top of the undercoat is greater than the sum of the dielectric strengths of the two coatings by themselves.
RELEVANT ART
US. Patent 3,619,259 and 3,911,202 disclose W
polymerization of continuous films which may be used for the purpose of electrical insulation.
US. Patents 4,184,001 and 4,268,659 disclose US
curable compositions specifically for use as insulation of electric wires.
3 50,541 US. Patent 4,317,858 discloses a W curable adhesive.
US. Patents 4,032,673 and 4,239,077 disclose US
curable resins for use in transformer coils.
DESCRIPTION OF THE INVENTION
The accompanying drawing is an isometric view in section of a certain presently preferred embodiment of an insulated conductor having an adhesive overcoat according to this invention.
In the drawing, conductors 1 are covered with a powder-coated insulation 2 over which has been applied a liquid resin 3 which has been B-staged with ultraviolet light at 4. At 5, the B-staged resin on adjacent strands of the conductor has been C-staged forming a solid mass 6.
The conductor used in this invention may be of any material, though it is typically a metal such as copper or aluminum. The conductor may be round or recta-galore wire or strip.
An insulating coating is applied over the con-doctor. The coating can be of almost any resin including epoxies, polyamides, polysulfones, polyester asides, and other resins. The coating is preferably an epoxy because those resins have the best combination of electrical, chemical, and mechanical properties for use in trays-former. (See, for example, US. Patents 4,D~8,809 and
US. Patents 4,032,673 and 4,239,077 disclose US
curable resins for use in transformer coils.
DESCRIPTION OF THE INVENTION
The accompanying drawing is an isometric view in section of a certain presently preferred embodiment of an insulated conductor having an adhesive overcoat according to this invention.
In the drawing, conductors 1 are covered with a powder-coated insulation 2 over which has been applied a liquid resin 3 which has been B-staged with ultraviolet light at 4. At 5, the B-staged resin on adjacent strands of the conductor has been C-staged forming a solid mass 6.
The conductor used in this invention may be of any material, though it is typically a metal such as copper or aluminum. The conductor may be round or recta-galore wire or strip.
An insulating coating is applied over the con-doctor. The coating can be of almost any resin including epoxies, polyamides, polysulfones, polyester asides, and other resins. The coating is preferably an epoxy because those resins have the best combination of electrical, chemical, and mechanical properties for use in trays-former. (See, for example, US. Patents 4,D~8,809 and
4,241,101.) The coating must be applied by a powder coating technique such as a fluidized bed, an electron static fluidized bed, or an electrostatic spray gun.
After the coating has been applied to the conductor, it is fully cured. The coating may be of any thickness but it is typically about 3 to about 8 miss. A description of a suitable powder coating process can be found in US.
Patent 4,127,695. Since the powder coating is typically cured by heat, it may be desirable to cool the coating in water or air prior to coating with the W adhesive.
Cooling may be desirable if the wire is to be wound on a spool before the US adhesive `- 4 I 50,541 is applied, but if the US adhesive is to be applied rimmed-lately, it may be desirable to have the powder coated wire warm so as to aid in the flow of the viscous W adhesive.
However, the powder coated wire should not be so hot that it cures the US adhesive to the C-stage. It is, of course, preferable to coat the powder coated wire with the W adhesive immediately in order to avoid the extra steps ox winding and unwinding the conductor.
The adhesive overcoat may be of any liquid resin which can be B-staged with ultraviolet light and thermally cured to the C-stage. This can be accomplished with an ultra-violet curable resin by only partially curing it to the B-stage and then completing the cure to the Stag using heat. However, it is more desirable to use a specially prepared resin which has two components W curable component and a heat-sensitive component. A two-component resin is easier to work with because the ultraviolet light can only cure it to the B-stage and thus it is not necessary to carefully control the exposure to ultra-violet light as it would be if the ultraviolet light could cure the resin all the way to the C-stage. An example of a two-component resin is given in Example 1, Composition A.
another suitable ultraviolet curable adhesive is described by F. I. Settler in US. Patent 4,317,858.
The adhesive overcoat must be a liquid, and it is preferably 100% solids to reduce air pollution and the cost of recover no solvents. Suitable resins include acrylated epoxies, cat ionic photo-initiated epoxies, ~hiol-polyene systems, and acrylo~urethanes. Acrylated epoxies are preferred as they have the best properties. A resin can be applied by reverse roller coating, by dipping and passing through a die or a wiper of leather or felt, or other technique. Reverse roller coating is preferred as it produces a thinner and more easily controlled coating.
After the adhesive overcoat has been applied, it is cured to the B-stage. The B-stage is the point at ~2~58 50,541 which the coating becomes dry, tack free, and non-blocking. This occurs when the resin is cured past its gelatin point. The cure to the B-stage is accomplished using ultraviolet light of a frequency and intensity which depend upon the particular composition used and the speed with which the conductor passes under the light. After the adhesive overcoat has been cured to the B-stage, the conductor can be wound onto reels or it can be used mime-doughtily. The stooged coating can be ox any thickness, but it is preferably about 0.25 to about I miss as a thinner coating has a poor bond strength and a thicker coating uses too much space.
In the next step of this invention strands of the conductor are placed side-by-side. The conductors with the adhesive overcoat may be used to form transformer coils, motor coils ! transposed cables, or other structures where the fusion of adjacent conductors into a solid mass would be desirable.
In the final step of this invention the adhesive overcoat is heated to complete its cure to the C-stage.
The temperature and time required to complete the cure will depend upon the particular adhesive overcoat compost-lion that is used.
The following examples further illustrate this invention.
A 0.114 x 0.289 inch rectangular aluminum wire was powder coated with an epoxy powder coating resin described in the example of US. Patents 4,241,101 or 4,088,809. The powder coating was cured in a wire tower at a speed of 10-53 ft/min and a tower temperature of 300-450C and had a thickness of 3 to 8 miss. After the powder coated wire had been fused and cured, short lengths of the powder coated wire were cut and an adhesive over-coat was brushed onto the wire by hand and cured to the B-stage under ultraviolet radiation. The following ultraviolet curable overcoats were used.
6 ~2~2~ 50,541 Composition (parts by weight) Ingredients _ A By C
Solid diglycidyl ether of bisphenol A
sold by Dow Chemical Co. as "DYER 662"55.356.4 55.7 Tetraethylene glycol diacrylate33.033.7 33.6 Triethanolamine borate in phenoxyethyl acrylate sold by Westinghouse as "WHITE" 8.3 8.4 8.2 Isopropyl Bunsen ether sold by Stouffer as "V-10" photoinitiator1.31.4 --Isobutyl Bunsen ether sold by Stouffer as "V_30't photo initiator 1.4 Fluorinated alkyd ester sold by 3~1 as "FC-430" Surfactant 2.1 -- 1.1 15 Picnic acid -- -- 0.01 Three pieces of the adhesive coated wire were clamped together overlapping about inch and were heated to 130~
for six hours in either air or in kerosene. After cooling the bonded sample were subjected to tensile shear testing I (double lap shear testing) at temperatures from 25 to 175C. The results era given in the following table.
Overcoat Test Composition Composition Composition C
Temp. (C) Bid. 3.0-4.0 old. 3.0-h.OBld. 2.5-4.0 Cured in Kerosene Cured in Air 1276 1757 2000~ 2708 loo 2486 This example shows that US sensitive adhesives can be formulated and applied to powder coated conductors with good tensile shear strengths at temperatures as high ~:lZ15-~
7 5~,541 as 175C. It also shows that bonding in kerosene does not adversely affect the bond strength of these adhesives.
EXAMPLE II
Rectangular aluminum wire (0.114 x 0.289 in) was coated with the powder disclosed in US. Patent 4,241,101 in a wire tower, then cured and spooled. Short lengths ~v12 in) were cut and straightened, then coated manually with two different US sensitive adhesives.
Composition A
"DYER 66~" epoxy resin 47.1 pow Limonene dioxide 31.3 pow Methyl tetrahydrophthalic android 15.7 pow ~liphatic triglycidyl ether sold by Sullenness as "5044" epoxy Rosen pow triaryl sulfonium hexafluoro phosphate sold by EM as "FC-S08" photo initiator 5.1 pow Chromium acetylacetonate 0.04 pow Composition B
"DYER 662" epoxy resin 45.5 pow 1,6-hexanediol diacrylate 6.9 pow 2-ethoxyethyl acrylate 9.2 pow Bottle glycidyl ether sold by Cuba Geigy as "RD-l" delineate 5.0 pow Diglycidyl ether of neopentyl glycol 5.0 pow Methyl tetrahydrophthalic android 15.0 pow "V-30" photo initiator 0.64 pow Chromium acetylacetonate 0.04 pow Wires overreacted with the above composition and B-staged were overlapped in pairs by a distance of 1 in.
along their long axes and subjected to a pressure of 50 - psi. The pairs were placed in a laboratory air circulate 8 50,541 in oven for 6 hours at 130C to C-stage the adhesive overcoats. After cooling, the bond pairs were tested for lap shear strength at 150C. The results were as follows (average of 5 samples):
Overcoat Lap Shear Strength (Pi ) Composition A 58 Composition B 154 After the adhesive had been Staged some samples were shelf aged for a period of 3 months.
The tensile shear test as described in Example I
was repeated. The results were as follows (average of 5 samples):
Overcoat Lap Shear Strength (psi) Composition A 51 Composition B 150 These results show that the W adhesives of this invention can be applied to powder coated conductors and can retain their tensile shear strength (single lap shear test) after shelf aging for periods of at least 3 months.
EXAMPLE III
Samples of 0.064 x .258 inch copper wire were coated with 4 miss of epoxy powder coating as in Example I. The samples were then coated with various adhesive overcoats including the same epoxy powder coating, Formvar and a W composition which consisted of Acrylated epoxy - 55.5% (50% phenoxyethyl acrylate);
W catalyst - 2.5%;
Hexamethoxymethyl mailmen (sold by American Cyanamid as "Camel 303"~ - 6.4%;
Rhenoxyethyl acrylate - 6.4%;
Vinyl acetate - 8.4%;
Epoxy novolac - 6.4%;
"WHITE" - 6.0%;
sly so, 541 Benzodimethyl melamines - 0.18% and blocked acrylated urethane - 6~2%;
Tetraethylene glycol diacrylate - 1.8%;
Catalyst Lowe (manufactured by American Cyanamid) - 0.03%;
Iron or chromium acetylacetonates - 0.03%
The ultraviolet adhesive overcoat was prepared in the following manner:
Three six inch samples were overlapped one inch lo and clamped together under a pressure of 10 psi. Beam tests were also performed on the samples. In a beam test, two beams 5 inches apart are placed under a stack of 5 wires bonded together and a third beam is pressed downward between the other two beams. The psi required to produce a failure are measured. The following. table shows the results.
Test Temperature Adhesive. T. 120C
Powder Coated Epoxy 480 650 Eormvar* 830 430 *a wire enamel which contains polyvinyl formal as a base resin. Other resins such as phenols, blocked .isocyanates, and mailmen formaldehyde are added, I depending on the supplier.
These results show that correctly formulated US
adhesives have beam shear strengths comparable to those of either powdered or solvent based adhesives when applied over powder coated conductors.
EXAMPLE V
A further benefit of using US sensitive over coats is a marked improvement in electric strength. A
spool of 0.064 x 0.258 copper rectangular wire was coated with powder manufactured by HAZEL and finely ground.
15~
50,541 Example I was repeated and the dielectric strength of samples with and without W overcoat were tested. The following table gives the results on 0.064 by 0.258 inch rectangular copper wire.
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After the coating has been applied to the conductor, it is fully cured. The coating may be of any thickness but it is typically about 3 to about 8 miss. A description of a suitable powder coating process can be found in US.
Patent 4,127,695. Since the powder coating is typically cured by heat, it may be desirable to cool the coating in water or air prior to coating with the W adhesive.
Cooling may be desirable if the wire is to be wound on a spool before the US adhesive `- 4 I 50,541 is applied, but if the US adhesive is to be applied rimmed-lately, it may be desirable to have the powder coated wire warm so as to aid in the flow of the viscous W adhesive.
However, the powder coated wire should not be so hot that it cures the US adhesive to the C-stage. It is, of course, preferable to coat the powder coated wire with the W adhesive immediately in order to avoid the extra steps ox winding and unwinding the conductor.
The adhesive overcoat may be of any liquid resin which can be B-staged with ultraviolet light and thermally cured to the C-stage. This can be accomplished with an ultra-violet curable resin by only partially curing it to the B-stage and then completing the cure to the Stag using heat. However, it is more desirable to use a specially prepared resin which has two components W curable component and a heat-sensitive component. A two-component resin is easier to work with because the ultraviolet light can only cure it to the B-stage and thus it is not necessary to carefully control the exposure to ultra-violet light as it would be if the ultraviolet light could cure the resin all the way to the C-stage. An example of a two-component resin is given in Example 1, Composition A.
another suitable ultraviolet curable adhesive is described by F. I. Settler in US. Patent 4,317,858.
The adhesive overcoat must be a liquid, and it is preferably 100% solids to reduce air pollution and the cost of recover no solvents. Suitable resins include acrylated epoxies, cat ionic photo-initiated epoxies, ~hiol-polyene systems, and acrylo~urethanes. Acrylated epoxies are preferred as they have the best properties. A resin can be applied by reverse roller coating, by dipping and passing through a die or a wiper of leather or felt, or other technique. Reverse roller coating is preferred as it produces a thinner and more easily controlled coating.
After the adhesive overcoat has been applied, it is cured to the B-stage. The B-stage is the point at ~2~58 50,541 which the coating becomes dry, tack free, and non-blocking. This occurs when the resin is cured past its gelatin point. The cure to the B-stage is accomplished using ultraviolet light of a frequency and intensity which depend upon the particular composition used and the speed with which the conductor passes under the light. After the adhesive overcoat has been cured to the B-stage, the conductor can be wound onto reels or it can be used mime-doughtily. The stooged coating can be ox any thickness, but it is preferably about 0.25 to about I miss as a thinner coating has a poor bond strength and a thicker coating uses too much space.
In the next step of this invention strands of the conductor are placed side-by-side. The conductors with the adhesive overcoat may be used to form transformer coils, motor coils ! transposed cables, or other structures where the fusion of adjacent conductors into a solid mass would be desirable.
In the final step of this invention the adhesive overcoat is heated to complete its cure to the C-stage.
The temperature and time required to complete the cure will depend upon the particular adhesive overcoat compost-lion that is used.
The following examples further illustrate this invention.
A 0.114 x 0.289 inch rectangular aluminum wire was powder coated with an epoxy powder coating resin described in the example of US. Patents 4,241,101 or 4,088,809. The powder coating was cured in a wire tower at a speed of 10-53 ft/min and a tower temperature of 300-450C and had a thickness of 3 to 8 miss. After the powder coated wire had been fused and cured, short lengths of the powder coated wire were cut and an adhesive over-coat was brushed onto the wire by hand and cured to the B-stage under ultraviolet radiation. The following ultraviolet curable overcoats were used.
6 ~2~2~ 50,541 Composition (parts by weight) Ingredients _ A By C
Solid diglycidyl ether of bisphenol A
sold by Dow Chemical Co. as "DYER 662"55.356.4 55.7 Tetraethylene glycol diacrylate33.033.7 33.6 Triethanolamine borate in phenoxyethyl acrylate sold by Westinghouse as "WHITE" 8.3 8.4 8.2 Isopropyl Bunsen ether sold by Stouffer as "V-10" photoinitiator1.31.4 --Isobutyl Bunsen ether sold by Stouffer as "V_30't photo initiator 1.4 Fluorinated alkyd ester sold by 3~1 as "FC-430" Surfactant 2.1 -- 1.1 15 Picnic acid -- -- 0.01 Three pieces of the adhesive coated wire were clamped together overlapping about inch and were heated to 130~
for six hours in either air or in kerosene. After cooling the bonded sample were subjected to tensile shear testing I (double lap shear testing) at temperatures from 25 to 175C. The results era given in the following table.
Overcoat Test Composition Composition Composition C
Temp. (C) Bid. 3.0-4.0 old. 3.0-h.OBld. 2.5-4.0 Cured in Kerosene Cured in Air 1276 1757 2000~ 2708 loo 2486 This example shows that US sensitive adhesives can be formulated and applied to powder coated conductors with good tensile shear strengths at temperatures as high ~:lZ15-~
7 5~,541 as 175C. It also shows that bonding in kerosene does not adversely affect the bond strength of these adhesives.
EXAMPLE II
Rectangular aluminum wire (0.114 x 0.289 in) was coated with the powder disclosed in US. Patent 4,241,101 in a wire tower, then cured and spooled. Short lengths ~v12 in) were cut and straightened, then coated manually with two different US sensitive adhesives.
Composition A
"DYER 66~" epoxy resin 47.1 pow Limonene dioxide 31.3 pow Methyl tetrahydrophthalic android 15.7 pow ~liphatic triglycidyl ether sold by Sullenness as "5044" epoxy Rosen pow triaryl sulfonium hexafluoro phosphate sold by EM as "FC-S08" photo initiator 5.1 pow Chromium acetylacetonate 0.04 pow Composition B
"DYER 662" epoxy resin 45.5 pow 1,6-hexanediol diacrylate 6.9 pow 2-ethoxyethyl acrylate 9.2 pow Bottle glycidyl ether sold by Cuba Geigy as "RD-l" delineate 5.0 pow Diglycidyl ether of neopentyl glycol 5.0 pow Methyl tetrahydrophthalic android 15.0 pow "V-30" photo initiator 0.64 pow Chromium acetylacetonate 0.04 pow Wires overreacted with the above composition and B-staged were overlapped in pairs by a distance of 1 in.
along their long axes and subjected to a pressure of 50 - psi. The pairs were placed in a laboratory air circulate 8 50,541 in oven for 6 hours at 130C to C-stage the adhesive overcoats. After cooling, the bond pairs were tested for lap shear strength at 150C. The results were as follows (average of 5 samples):
Overcoat Lap Shear Strength (Pi ) Composition A 58 Composition B 154 After the adhesive had been Staged some samples were shelf aged for a period of 3 months.
The tensile shear test as described in Example I
was repeated. The results were as follows (average of 5 samples):
Overcoat Lap Shear Strength (psi) Composition A 51 Composition B 150 These results show that the W adhesives of this invention can be applied to powder coated conductors and can retain their tensile shear strength (single lap shear test) after shelf aging for periods of at least 3 months.
EXAMPLE III
Samples of 0.064 x .258 inch copper wire were coated with 4 miss of epoxy powder coating as in Example I. The samples were then coated with various adhesive overcoats including the same epoxy powder coating, Formvar and a W composition which consisted of Acrylated epoxy - 55.5% (50% phenoxyethyl acrylate);
W catalyst - 2.5%;
Hexamethoxymethyl mailmen (sold by American Cyanamid as "Camel 303"~ - 6.4%;
Rhenoxyethyl acrylate - 6.4%;
Vinyl acetate - 8.4%;
Epoxy novolac - 6.4%;
"WHITE" - 6.0%;
sly so, 541 Benzodimethyl melamines - 0.18% and blocked acrylated urethane - 6~2%;
Tetraethylene glycol diacrylate - 1.8%;
Catalyst Lowe (manufactured by American Cyanamid) - 0.03%;
Iron or chromium acetylacetonates - 0.03%
The ultraviolet adhesive overcoat was prepared in the following manner:
Three six inch samples were overlapped one inch lo and clamped together under a pressure of 10 psi. Beam tests were also performed on the samples. In a beam test, two beams 5 inches apart are placed under a stack of 5 wires bonded together and a third beam is pressed downward between the other two beams. The psi required to produce a failure are measured. The following. table shows the results.
Test Temperature Adhesive. T. 120C
Powder Coated Epoxy 480 650 Eormvar* 830 430 *a wire enamel which contains polyvinyl formal as a base resin. Other resins such as phenols, blocked .isocyanates, and mailmen formaldehyde are added, I depending on the supplier.
These results show that correctly formulated US
adhesives have beam shear strengths comparable to those of either powdered or solvent based adhesives when applied over powder coated conductors.
EXAMPLE V
A further benefit of using US sensitive over coats is a marked improvement in electric strength. A
spool of 0.064 x 0.258 copper rectangular wire was coated with powder manufactured by HAZEL and finely ground.
15~
50,541 Example I was repeated and the dielectric strength of samples with and without W overcoat were tested. The following table gives the results on 0.064 by 0.258 inch rectangular copper wire.
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o o a a), O U O 1:4 I ~1 a I h Al h rl a u U I O Us O I a I o I 0 O rl Us ^ - us o Jo m O a ,,; .--,., 12 50,541 EXAMPLE VI
Three samples of rectangular aluminum wire coated with the same powder used in Example I were dipped into a W sensitive resin comprised of:
"DYER 662" epoxy resin 502.5 g "WHITE" 75.0 Tetraethylene glycol diacrylate200.0 Ethyl Huxley acrylate 150.0 2-hydroxy ethyl acrylate 37.5 lo "V-10" photo initiator 3.75 Tert-butyl perbenzoate 3.75 Excess resin was wiped off and the coating was irradiated for 8 minutes under a source of ultraviolet light.
After the irradiation, the coating was dry to the touch and measured 3.5 mix (addition to the thick-Nazi.
The three samples were pressed together under nominal spring pressure (from a bulldog clip) at 150C for I hours.
AYE double lap-shear test gave a test value ox 184 lobs. on the two adhered areas of 0.350 x 0.258 in., equip-alert to Lowe psi.
Ed Jo -I Jo O
o o a a), O U O 1:4 I ~1 a I h Al h rl a u U I O Us O I a I o I 0 O rl Us ^ - us o Jo m O a ,,; .--,., 12 50,541 EXAMPLE VI
Three samples of rectangular aluminum wire coated with the same powder used in Example I were dipped into a W sensitive resin comprised of:
"DYER 662" epoxy resin 502.5 g "WHITE" 75.0 Tetraethylene glycol diacrylate200.0 Ethyl Huxley acrylate 150.0 2-hydroxy ethyl acrylate 37.5 lo "V-10" photo initiator 3.75 Tert-butyl perbenzoate 3.75 Excess resin was wiped off and the coating was irradiated for 8 minutes under a source of ultraviolet light.
After the irradiation, the coating was dry to the touch and measured 3.5 mix (addition to the thick-Nazi.
The three samples were pressed together under nominal spring pressure (from a bulldog clip) at 150C for I hours.
AYE double lap-shear test gave a test value ox 184 lobs. on the two adhered areas of 0.350 x 0.258 in., equip-alert to Lowe psi.
Claims (16)
1. An article comprising a conductor coated with a fused and cured resin powder applied insulating coating, over which is a coating of an ultraviolet B-stageable, thermally C-stageable liquid resin.
2. An article according to Claim 1 wherein said conductor is an aluminum or copper wire.
3. An article according to Claim 1 wherein said insulating coating is an epoxy resin.
4. An article according to Claim 1 wherein said insulating coating is about 3 to about 8 mils thick.
5. An article according to Claim 1 wherein said liquid resin is an acrylated epoxy.
6. An article according to Claim 1 wherein said liquid resin is solventless.
7. An article according to Claim 1 wherein said coating has been cured to the B-stage with ultraviolet light.
8. An article according to Claim 7 wherein strands of said conductor are placed side-by-side and said coating is cured to the C-stage.
9. An article according to Claim 8 in the form of a transformer coil.
10. A method of bonding conductors insulated with a fused and cured powder coating into a solid mass comprising:
(a) coating said conductors with an ultraviolet B-stageable, thermally C-stageable liquid resin;
(b) curing said liquid resin to the B-stage with ultraviolet light;
(c) juxtaposing strands of said conductor; and (d) thermally curing said liquid resin to the C-stage.
(a) coating said conductors with an ultraviolet B-stageable, thermally C-stageable liquid resin;
(b) curing said liquid resin to the B-stage with ultraviolet light;
(c) juxtaposing strands of said conductor; and (d) thermally curing said liquid resin to the C-stage.
11. A method according to Claim 10 wherein said conductor is an aluminum or copper wire.
12. A method according to Claim 10 wherein said powder coating is an epoxy resin.
13. A method according to Claim 10 wherein said insulating coating is about 3 to about 8 mils thick.
14. A method according to Claim 10 wherein said liquid resin is an acrylated epoxy.
15. A method according to Claim 10 wherein said liquid resin is 100% solids.
16. A method according to Claim 10 wherein said juxtaposed strands form a transformer coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000446630A CA1212158A (en) | 1984-02-02 | 1984-02-02 | Insulated conductor having adhesive overcoat |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000446630A CA1212158A (en) | 1984-02-02 | 1984-02-02 | Insulated conductor having adhesive overcoat |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1212158A true CA1212158A (en) | 1986-09-30 |
Family
ID=4127092
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000446630A Expired CA1212158A (en) | 1984-02-02 | 1984-02-02 | Insulated conductor having adhesive overcoat |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1212158A (en) |
-
1984
- 1984-02-02 CA CA000446630A patent/CA1212158A/en not_active Expired
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